1. Field of the Invention
The invention relates in general to a full-zone optical image addressing apparatus, and more particularly, to an apparatus and a method using the addressing information of addressing patterns to perform full-zone addressing for a scanner.
2. Related Art of the Invention
In the basic structure of a typical scanner, an optical scan module (chassis) 111 and a driver structure 112 are included as shown in FIG. 1. The optical scan module 111 includes an image extraction device (not shown) to extract the image of the object to be scanned. An analog/digital converter converts the scanned image into digital data to be processed subsequently. Therefore, when the scanner starts scanning, the whole optical scan module 111 is driven by the driver structure 112, such that the image extraction device and the analog/digital converter perform image extraction and digital/analog conversion, respectively.
The driver structure 112 further comprises a driving motor and a guiding device (not shown). The driving motor includes a DC motor or stepping motor. When the DC motor is used as the driving motor for scanning, only the scanning speed is controlled to be gradually increased or gradually decreased. The address or position at certain time during the scanning process cannot be realized. As a result, the scan timing and address information for each line of the scanned document cannot be obtained. This increases the difficulty in the subsequent scanned image processing since there is no reference address to be referred for reassembling scanned lines into a complete scanned image.
The application of the stepping motor controls each scan line to be output in sequence in the subsequent image-processing step, the scanned image can be assembled in a first-in-first-out arrangement. However, such an arrangement is problematic for color scanner. Each scan line scanned by the color scanner has three sets of image information (R, G, B). Therefore, the image processes such as reassembly, compensation and correction all require address information as a reference for adjustment. Otherwise, the scanned image observed by the user may include chromatic aberration or distortion
A prior art image scanning apparatus and fast addressing method have been proposed, for example, in the Taiwanese patent No. 408552. As shown in FIG. 1 in this disclosure, an object 13 to be scanned is placed on a scan platform 12. The scan platform includes an initial scan line 121, a marking pattern 14 printed by optical black, and a region 15 completed by correction white. The distance between a specific point A of the marking pattern 14 and the scan initial line 121 is referred to as predetermined length Yb. When the driver device 112 drives the image extraction device to start extracting the image, reference point coordinates c and b of the marking pattern 14 are obtained. A function of the angle between the reference point coordinates c, b and the specific point A of the marking pattern 14 is obtained. According to the predetermined length Yb, the reference point coordinates c and d, and the function of .theta., the scanner chassis can be quickly addressed in the scan initial line 121.
However, the prior art technique can only address the initial scanning position, but fails to provide the addressing technique during the scanning process. Therefore, when an external force such as vibration causes deviation of the addressing point, the image color is easily distorted.